Rechargeable high performance batteries, such as Li-ion batteries, are widely used today to power electric vehicles. In such environments, the batteries can experience exceptionally high loads as a result of, for example, rapid acceleration or rapid breaking. Such high loads can generate large electrical currents which in turn may result in a significant warming of the Li-ion cells due to their internal resistance. This generation of waste heat and resulting warming cannot be ignored.
In the case of Li-ion batteries, for example, achieving efficient operation requires that they must be operated within a specific temperature range. At operating temperatures greater than about 40° C., the life span of the battery can be significantly reduced. In addition, the temperature gradient among cells in a multi-cell battery must be kept within 5-10 degrees centigrade.
As a consequence, it is essential to have an effective cooling system for such batteries. The cooling system should provide a way to dispose of the waste heat while at the same time assuring that excessive thermal gradients do not occur within the multi-cell battery. It is also desirable that the cooling system be inexpensive and lightweight.